The present invention is concerned with containers for flowable materials, and, more particularly, with containers for liquids in which the pressure is greater than atmospheric. It will be appreciated that carbonated beverages such as the so-called soft drinks and brewed beverages such as beer and cider are contained at super-atmospheric pressure, but the present invention is also concerned with flowable materials (including other liquids) that are, or can be, contained at super-atmospheric pressure. In particular, it is not uncommon for a number of xe2x80x9cstillxe2x80x9d drinks to be packaged in a container containing an atmosphere of nitrogen at super-atmospheric pressure. Examples of the goods which are, or can be, packaged in this way include juices and juice-drinks, milk and milk-based drinks, spirits, wines, iced teas and tea drinks and even medicines and pharmaceuticals delivered in liquid form.
In certain alcoholic beverages, particularly stouts, a thick head of creamy froth has long been considered desirable. This head is readily generated when a stout is poured from conventional beer-dispensing apparatus but when stouts are contained in cans (as many other alcoholic beverages frequently are) a head of the same quality is often not produced upon opening the can. This has provided a disincentive to the sale of such beverages in cans but Australian patent No. 577486 provides a solution to this problem. The can described in Australian patent No. 577486 includes an insert which is a gas-filled chamber in communication with the beverage in the can through a restricted orifice. Since the chamber is immersed in the beverage contained in the can a small amount of the beverage will enter the chamber through the restricted orifice so as to equilibrate the pressure in the head space of the chamber and the pressure in the head space of the can. Upon opening the can, the pressure in the head space of the can will immediately be reduced to atmospheric while the procure in the head space of the secondary chamber will remain, momentarily at least, at a pressure greater than atmospheric, hence the gas and/or beverage in the chamber will be ejected through the restricted orifice. This causes gas in the solution to be evolved and form a head of creamy froth on the beverage. The patent does not, however, envisage the introduction of a second liquid into the beverage upon opening of the can, and this would not be possible with the arrangement described since the beverage and any liquid contained in the secondary chamber would be free to mix whilst the can remained sealed.
There are numerous patents and patent applications filed subsequent to Australian patent No. 577486 concerned with the introduction of a head of froth to, beer in a container, but none envisages a container suitable for the introduction of a second liquid to the packaged beverage. However, it would be desirable for a container to be able to contain a second flowable material (such as a powder, suspension or liquid) in a chamber separate to the main chamber of a pressurised container so that it may be introduced subsequently to the beverage in the container. It will be appreciated that such a container, although adapted to introduce a second flowable material to the packaged beverage, could also introduce gas or a separately contained, pressurised beverage into the container so as to cause the beverage to foam.
Such a container is described in international application No. PCT/GB95/01185 in which two such compartments are separated by a membrane capable of being grossly ruptured by the release of pressure when the container is opened. In this case, one compartment contains whisky and the other soda water, hence when the membrane is ruptured a whisky and soda drink is produced. Similarly, U.S. Pat. No. 4,524,078 describes a container including a capsule which either has a separable cap, a frangible wall or in which one wall comprises a wall of the container and the capsule is forced away from the wall of the container when the container is opened. In each case either a wall ruptures, a component of the capsule separates from the capsule or the entire capsule separates explosively from its anchor and may fragment, so in each case there is a potential choking hazard created by the formation of small pieces of the capsule within the beverage in the can. Furthermore, in each case the encapsulated liquid will be released relatively gently through a large orifice into the beverage in the container, so it will diffuse relatively gradually into the beverage. This may result in incomplete mixing and does not provide for spectacular visual effects.
International patent application No. PCT/EP94/02491 describes an arrangement in which a capsule with an orifice in its bottom face is secured in the lower portion of a pressurised beverage can. The capsule contains a second liquid miscible with the primary liquid contained in the can and, to avoid mixing of the two liquids prior to opening of the can, includes a valve stem which seals the orifice in the bottom face of the capsule. The bottom face of the capsule is, however, flexible and when a pressure differential is created by opening the can, the bottom face of the capsule flexes downwardly and the valve stem is dislodged. This allows the second liquid to enter the can through the orifice and mix with the primary liquid. It would be difficult to insert the capsule since it must be pressurised prior to insertion but the open can into which it is inserted will not be pressurised until after it is sealed. Thus there would be practical difficulties in ensuring that the second liquid does not leak through the orifice during insertion. Furthermore, such an arrangement is likely to be subject to pressure fluctuations, for example due to temperature change, in the head space within the capsule. Since there is no means of equalising the pressure within the head space in the capsule with the pressure in the head space within the can, such minor pressure fluctuations will create a pressure differential whenever the temperature of the can changes. This differential will result in small fluctuations in the position of the bottom wall of the capsule and may result in leakage, since it is critical that the orifice remain hard against the valve seat at all times to avoid leakage.
The present invention aims to provide an arrangement for containing a fist flowable material and a second flowable material separately in a pressurised container and for injecting the second flowable material into the first flowable material when the pressurised container is opened. Moreover, having provided such an arrangement, it was recognised that it could also be applicable to injecting gas or a separately contained, pressurised second flowable material into the first flowable material.
The invention generally provides a container for separately containing a first flowable material and a second flowable material until mixing of the first and second flowable materials is desired comprising:
(i) a first chamber containing the first flowable material and having a first head space comprising gas at a pressure greater than or equal to atmosphere pressure;
(ii) a second chamber containing the second flowable material, the second flowable material containing gas, and optionally, the second chamber comprising a second head space containing gas at a pressure greater than atmospheric pressure;
(ii) means for reducing the pressure in the first chamber;
(iv) means for transferring gas between the first and second chambers; and
(v) means for transferring the second flowable material into the first flowable material when the pressure in the first chamber is reduced.
Preferably, the means for reducing the pressure in the first chamber take the form of means for opening the first chamber to an environment external to that chamber, the external environment being at a pressure lower than the pressure in the first chamber before the first chamber is exposed to that external environment. A particularly preferred way of achieving this would be to provide the container with means for opening the first chamber to the atmosphere. Such means could take the form of, for example, a screwable/unscrewable cap fitted to a bottle, a lift off tab for a bottle or can, or a structure located on a wall of the container which is able to be pushed in so as to create an opening in the container communicating between the first chamber and its external environment. Such means would readily be comprehended by persons of ordinary skill in the art. Accordingly, wherever reference is made in this specification and the appended claims to xe2x80x9cmeans for reducing the pressure in the first chamberxe2x80x9d is to be understood that such references include a reference to all means of the type discussed in this paragraph.
Preferably, the second chamber has a second head space and the means for transferring the gas between the first and second chambers comprise means for establishing a pressure equilibrium between the first head space and the second head space. It will be appreciated by those of skill in the art that the term xe2x80x9cequilibriumxe2x80x9d in the context of the balance of pressures between the first and second head spaces should not be taken as implying that the pressures in the first and second head spaces are necessarily equal or approximately equal. In fact, as detailed below, there may actually be a pressure gradient between the first and second head spaces, but nonetheless, an equilibrium will exist between the pressures in the two chambers. In a typical embodiment of the invention, the arrangement would thus be that the pressure in the first chamber (prior to it being opened to its external environment), would be a pressure greater than atmospheric pressure. It is preferred that prior to activating the mixing of the first flowable material and the second flowable material, the pressure in the first and second head spaces is about equal. As explained above however, in other forms of the invention, there may be a difference between the pressure in the first and second head spaces. In embodiments of the invention where such a pressure differential applies, preferably, the difference between the first and second head spaces lies in the range of from about 0.1 to about 10 atmospheres.
Preferably, the pressure in each of the first and second head spaces is at least 0.1 atmosphere, gauge pressure, prior to activation of the container and in order to mix the first and second flowable materials. It is particularly preferred that pressure is at least 0.5 atmosphere, and even more preferably, at least 1 atmosphere. Therefore, the pressure in each of the first and second head spaces is preferably at least one atmosphere above atmospheric pressure, prior to the mixing of the fist and second flowable materials.
It is to be understood that unless the context otherwise requires, wherever used in this specification, the term xe2x80x9cflowable materialxe2x80x9d includes liquids, solutions, suspensions, emulsions, gases and any other forms of matter colloquially referred to or known as a xe2x80x9cliquidxe2x80x9d or a xe2x80x9cfluidxe2x80x9d, as well as other flowable materials, such as powders. The first and the second flowable materials may be materials of the same physical character, or of different kinds. In one preferred form of the invention, each of the first and second flowable materials would comprise true liquids. In yet other forms of the invention however, the first flowable material could take the form of a true liquid, and the second flowable material could (for example) take the form of a powder. Those of ordinary skill in the art will readily appreciate that many other combinations are possible, and are embraced within the scope of the present invention. Such persons would also readily appreciate that the flowable material in either chamber couldxe2x80x94prior to mixing with the flowable material in the other chamberxe2x80x94also constitute a combination of two or more flowable materials (eg, a liquid containing a gas).
Preferably, the means for transferring the second flowable material comprise a conduit means extending from within the reservoir of the second flowable material in the second chamber into the first head space. Alternatively, the conduit may terminate within the first flowable material, in which case it would be desirable to include a siphon breaker arrangement such as a small orifice in the conduit means within the first head space. More preferably, the conduit means passes through the second head space.
Preferably, the conduit means comprise a structure through which the flowable material may travel. Preferred structures for this purpose include tubes, and channels (including enclosed and open channels). Alternatively, the structure could take the form of one or more bores formed through a wall or like partition separating the two chambers of the apparatus. A particularly preferred conduit means would include a capillary structure, such as (for example), a capillary tube. In this regard, it is to be understood that wherever used in this specification, the term xe2x80x9ccapillaryxe2x80x9d includes not only structures or apparatus which are thin or of hair-like configuration, but also, other structures or apparatus which are capable of employing a capillary action.
In a particularly preferred embodiment of the invention, the means for equilibrating pressure comprises a small orifice in the conduit means within the second head space. The orifice may be a round hole but could equally well be an oblate or square hole, a slot, or the like. It will be appreciated that gradual pressurisation and depressurisation of the second head space occurs when the orifice is present since the orifice is in direct fluid communication through the conduit means and the orifice in its end (or the orifice operating as a siphon breaker) with the first head space. However, when rapid depressurisation of the first chamber occurs, a pressure differential will be created between the first chamber and the second chamber as the orifice is sufficiently small that a large pressure differential such as created when the first chamber is opened to the atmosphere cannot be equilibrated instantaneously. Accordingly, there will an initial flow of the second flowable material through the conduit means, and the initial flow will quickly block the small orifice. Thus, the pressure differential created by opening the first chamber to the atmosphere cannot be equilibrated and flow of the second flowable material through the conduit means it will continue until there is no longer sufficient pressure differential to drive that flow.
Preferably, the transfer mechanism additionally comprises means whereby the second flowable material travels through the second head space, prior to entering the first chamber. This arrangement would prevent the second flowable material from entering the first chamber by leakage through gravity, unless and until it is transferred from the second chamber by equilibration of pressures between the first and second chambers, as described earlier. In this manner, the container would effectively provide a xe2x80x9cliquid lockxe2x80x9d, thereby preventing premature transfer of the second flowable material into the first flowable material, until transfer is activated in accordance with the invention. Advantageously, the orifice remains above the level of the second flowable material, even if the container is laid on its side. In this arrangement the second flowable material cannot block the orifice at any time except when flow of the second flowable material through the conduit means is induced by opening the first chamber to the atmosphere. This will minimise the possibility of leakage when the container is laid on its side as any small pressure differentials created due to fluctuations in temperature or the like will be quickly equilibrated, irrespective of the orientation of the container.
It may at times be desirable to provide an orifice adapted to be variable in size. For example, the orifice may be fully opened when the first chamber is fully pressurised to ensure that effectively, no pressure differential is created between the first chamber and the second chamber, but the orifice could be restricted or closed when the first chamber is about to be opened to the atmosphere. In the former case this ensures that the orifice is effectively closed by the second flowable material during depressurisation of the first chamber and in the latter case equilibration of pressure is prevented entirely for a period of time prior to opening the first chamber to the atmosphere. In each case, the arrangement facilitates the transfer of the second flowable material whilst minimising the possibility of leakage when the container is in the unopened condition, since the exchange of gases between the first chamber and the second chamber will be enhanced in that condition. This is particularly so because one can use an orifice larger than that which would ensure adequate discharge of the second flowable material if its diameter can be restricted prior to discharge.
The orifice may comprise a slit or valve formed in the capillary. The slit or valve will be closed when the pressure differential between the first chamber and the second chamber is less than a predetermined amount. The predetermined amount is, preferably, between 0.1 atmospheres and 2 atmospheres, gauge pressure. When the pressure in the first chamber exceeds the pressure in the second chamber by more than this predetermined amount, the slit or valve will open and allow the pressure in the two chambers to reach an equilibrium. It will be appreciated by those of skill in the art that in the case of a typical carbonated beverage container made in accordance to the invention, the pressure differential arising when discharge occurs is of the order of 0.5 atmospheres, so this differential will of course, open the small orifice, but the orifice is too small far such a large pressure differential to be equilibrated. The advantage of using a slit which is closed when no pressure differential, or only a small pressure differential less than the predetermined amount, exists, is that leakage of the second flowable material is minimised.
Any other suitable means of equilibrating the pressure between the first head space and the second head space may be employed. For example, the second chamber could be made of or include a portion of a gas permeable plastic such as low density polyethylene, high impact polystyrene, polycarbonate, co-polymers of two or more such plastics materials, or the like. In this embodiment of the invention, diffusion of gas through the gas permeable plastic impregnates the second flowable material in a second chamber containing that flowable material. The entire capsule could be made out of a gas permeable plastic, however, in some applications of the invention, it is preferable to make the capsule out of a plastic which is relatively non-permeable to gas and to make the conduit means (including those parts of it which are in contact with the first head space) out of a gas permeable plastic. In this case, the conduit means does not require an orifice to be formed therein, but rather the gas merely diffuses through the plastic forming the conduit means. Alternatively, a portion of the conduit means may be made of a gas permeable plastic. A particularly suitable gas permeable plastic is low density polyethylene, although other gas permeable plastics are known which are also suitable. Alternatively, part of the capsule (other than the conduit means) could be made out of a gas permeable plastic.
Advantageously, the second chamber floats on the top of the first flowable material, or is fixed to the container at or above the level of the first flowable material. In the case of the container taking the form of a bottle, the second chamber may be fixed to the underside of the cap. In this last mentioned embodiment, the second chamber is preferably located adjacent to or below the cap, but is attached to the neck of the bottle.
In any such arrangement, the second head space and the first head space are separated merely by the walls of the second chamber. In this case it is advantageous for the conduit means to consist of a capillary or a structure otherwise defining a channel. Examples of suitable structures include a gooseneck capillary, or a concentric pipe arrangement. Typically, a capillary or channel-defining structure comprises a first vertical portion extending from within the reservoir of the second flowable material in the second chamber into the second head space, a horizontal portion extending through the wall of the second chamber into the first head space and a second vertical portion within the first head space to direct the second flowable material, when ejected from the second chamber, into the first flowable material. The orifice, to allow equilibration of the pressures in the first and second head spaces, could be in any part of the capillary or channel-defining structure, provided it is above the level of the second flowable material.
Alternatively such a capillary or channel-defining structure may comprise a first vertical position extending from within the reservoir of the second flowable material in the second chamber into the second head space, a horizontal portion within the second head space and a second vertical portion extending from the second head space through the second liquid (but without any means of communicating therewith) and then through a bottom wall of the second chamber into the first head space. The orifice or valve to allow equalisation of the pressures in the first and second head spaces could be in the horizontal portion of the capillary or channel-defining structure, but could also be in either the first or second vertical portions of such a structure provided it is above the level of the second flowable material.
Advantageously, means are also provided to keep the orifice above the level of the second flowable material, even if the container is laid on its side. Typically this is achieved by ensuring that the second flowable material is filled only to a predetermined level and that the orifice is in a position which is above that level, irrespective of the orientation of the container, although of course it will be appreciated the total inversion of the container or some other inappropriate handling could immerse the orifice. It may also be necessary for the container to be packaged in such a way that it cannot be positioned in certain orientations.
There may be more than one such orifice. Advantageously, a first such orifice is located in the first vertical portion not far above the surface of the second flowable material and a second such orifice is located further from the second flowable material in the first vertical portion or in the second vertical portion or the horizontal portion. Thus, should the surface tension in the second flowable material be sufficient for it to move up the capillary far enough to block the first orifice, gas exchange can still occur through the second orifice. A non-wetting agent could be added to the second flowable material or coated onto the inside of the capillary to minimise movement of the second flowable material into the capillary prior to discharge.
A mechanical barrier on the end of the first vertical portion could be employed to prevent entry of the second flowable material into the first vertical portion of the capillary/channel defining structure. A suitable barrier could comprise a cap secured to the bottom wall of the second chamber and able to receive the end of the first vertical portion of the capillary, the cap having a small orifice formed in its side. The first vertical portion of the capillary/structure, when received in the cap, closes the small orifice in the side of the cap but, when it moves away from the bottom of the second chamber, for example when the cap of the container (in this case, in the form of a bottle) is unscrewed, the small orifice is opened. Accordingly, entry of the second liquid to the capillary/structure is prevented while the bottle is closed but opening the bottle brings the end of the first vertical portion of the capillary into a position where the small orifice in the cap is no longer sealed and discharge can occur.
In a particularly preferred embodiment of the invention, the horizontal portion of the capillary abuts the underside of the cap of a bottle and the capillary is adapted for folding movement in the vicinity of the orifice. Typically this folding movement occurs in response to pressure applied, generally manually, to the bottle cap and causes the capillary to fold in such a manner as to restrict or close the orifice. Thus, digital pressure can be applied to the cap of a bottle just prior to opening, or as a part of the opening action, to restrict or close the orifice.
Advantageously, back flow prevention means are provided in the capillary to ensure that the first flowable material does not flow through the capillary into the second chamber, for example, when the container is laid on its side. Such back flow prevention means may comprise a simple flap of a suitable material secured within the capillary in such a manner as to prevent flow of the flowable material from the fist chamber into the second chamber but to allow the flow of the second flowable material from the second chamber into the first chamber. Typically the flap is located in the second vertical portion of the capillary very near its opening to the first chamber. If desired, a one-way valve could be used in place of the flap of material.
Alternative means could be used for transferring the second flowable material. When the second chamber is mounted above the level of the first flowable material, for example, by being fixed to the container or to the underside of a cap, the second liquid may be transferred (for example, by injection) through an orifice formed in a bottom wall of the second chamber. The orifice will be sealed whilst there is no pressure differential between the first chamber and the second chamber but when the first chamber is suddenly depressurised upon opening to the atmosphere, the orifice will be opened. This may be accomplished, for example, by covering the orifice with a burstable sealing strip which ruptures on opening of the container, or by various arrangements of valve means. Suitable valve means for this purpose include an orifice that is opened by relative movement (ie, separation) apart of opposed walls structurally defining or forming part of the bottom wall of the second chamber, poppet valves in the bottom wall and the like.
One particularly suitable arrangement comprises a valve stem fixed in the orifice prior to screwing on the cap of a bottle but adapted for capture by the cap as the cap is screwed on, whereupon when the cap is unscrewed the valve stem is unseated from the orifice. Alternatively, the valve stem may be secured to the cap throughout the closing operation but has a sharp-end which pierces the bottom wall of the second chamber forming the orifice, but sealing it as it is created. Once again, opening cap results in withdrawal of the valve stem from the orifice and so the second flowable material is released. In a yet further arrangement, the means for transferring the second flowable material could comprise a conduit means in the form of a stand pipe which is concentrically located within the second chamber, adapted for capture with the cap of a bottle as the cap is fitted to the bottle, and which also has an associated valve means located at the top or the bottom of the stand pipe, wherein the transfer of the second flowable material into the first flowable material is activated by opening the cap. The opening of the cap may be actuated by unscrewing it, by a lift off mechanism, or by other means which would readily be apparent to those skilled in the art.
In another arrangement that could be used, either the bottom or the top wall of the container is flexible and the orifice is closed by sealing against a valve stem affixed to the top wall of the second chamber opposite the orifice when pressure is equilibrated between the first chamber and the second chamber. However, the bottom wall (or the top wall, as the case may be) flexes when the first chamber is equilibrated and so moves away from the valve stem, thereby opening the orifice.
Alternatively, and this arrangement can be used more particularly where conduit means such as a capillary or channel-defining structure as described above are employed, the top or bottom wall of the container is flexible but seals against the opening of the conduit means to the second flowable material when pressure in the first chamber and the second chamber is equilibrated, but flexes away from it when the first chamber is depressurised.
Yet another possible arrangement has a bottom or top wall which is not particularly flexible but is able to deform sufficiently to form a seal when held against the opening of the conduit means. In this arrangement the conduit means and the bottom or top wall are arranged so as to come into sealing contact when the cap is in sealed disposition on a bottle form of the container but to move away from sealing contact as the cap moves upwardly on the crown of the bottle during the unsealing operation. More particularly, in a screw-cap arrangement, sealing contact is first made as the cap is screwed on after filling the bottle, is maintained whilst the bottle remains capped, and is broken as the cap is unscrewed.
The invention further provides a container for separately containing a first flowable material and a second flowable material until it is desired to mix those materials, comprising:
(a) a first chamber containing the first flowable material, and having a first head space comprising gas at a pressure equal to or greater than atmospheric pressure;
(b) a second chamber containing a second flowable material and comprising a gas at a pressure greater than atmospheric pressure, the second chamber having a base part located generally at or towards a lower part of the first chamber and further comprising conduit means extending from the base part towards the surface of the first flowable material; and
(c) means for opening the first chamber to the atmosphere so as thereby to cause the second flowable material to be transferred into the first flowable material.
The container may also comprise means for equilibrating the pressure in the first and second chambers, prior to opening the first chamber to the atmosphere. For example, a tube, channel or other conduit means extending from the second head space to the first head space could be employed for this purpose.
Those of skill in the art will appreciate that in the absence of providing such pressure equilibration means, the pressures in the first and second chambers should be substantially equal. Hence, the second chamber must be introduced into the container at; a time when (i) the second chamber is pressurised and (ii) the first chamber is yet to be pressurised.
The present invention also provides a method of filling a container in accordance with the last mentioned aspect of the present invention, comprising the steps of:
(1) introducing the second flowable material into the second chamber;
(2) pressurising the second chamber;
(3) freezing at least a portion of the second flowable material so as to close the conduit means with frozen second flowable material;
(4) inserting the second chamber in the first chamber and introducing the first flowable material into the first chamber;
(5) sealing the first chamber; and
(6) heating the container.
It will be appreciated that upon heating, for example in the pasteurisation process, the plug of the second flowable material closing the conduit means melts. However, an air lock barrier will be set up within the conduit means to partition the second flowable material from the first flowable material, thereby preventing mixing.
Alternatively, a thermoplastic material could be used to form a plug which will melt when the container is heated, or a burstable seal could be provided to close off the conduit means, provided that the seal will burst upon a pressure differential being established between the second chamber, and the first chamber, upon opening of the first chamber to the atmosphere.
It will be appreciated by persons skilled in the art that any of the embodiments of the invention described above may include a plurality of chambers (rather than a single second chamber), capable of delivering a plurality of different flowable materials. It will also be appreciated that different flowable materials could be transferred from different chambers in the same insert or could be transferred from separate inserts.
Typically the second chamber is substantially smaller in volume than the first chamber. In general, it is only necessary to deliver small volumes of the second flowable material to the first flowable material. In general, in the context of a beverage container, between 1 and 90% of the second head space is occupied by the second flowable material.
Typically the first flowable material is a beverage.
In one embodiment of the invention, (in which the container contains a beverage), the second flowable material comprises a colouring such as a 1% solution of tartrazine, sunset yellow, carmoisine or brilliant blue. Advantageously when the container containing the beverage and the tartrazine solution is opened, a colour change to the first liquid (ie, the beverage) occurs, providing a dramatic visual effect which may be transient, persisting only for a few seconds after the bottle is opened, or may be relatively long-lasting. An example of the latter would be a situation where a twist or pattern of colour is produced in the liquid. Alternatively, a substantial volume of coloured liquid may be transferred, so as to create a two-layer effect in the container. Clearly the creation of a two-layer effect is reliant on the second liquid having a density very different from that of the first liquid. In general, the second liquid would be floated on top of the first liquid but if injected from the bottom of the container, the second liquid may constitute the bottom layer of liquid.
The second liquid could also be or contain a flavouring, which may or may not be colourless. Suitable flavouring systems are essential oils in ethyl alcohol compounded flavour chemicals and essential oils with ethyl alcohol and water compounded flavour chemical with propylene glycol and essential oils wetted with wetting agents in, aqueous solution with surfactants. Typically the flavours are present in 0.01-0.2% v/v. Examples of essential oils are citrus oils such as lemon, lime and orange (distilled and cold pressed), and natural spice oils such as cinnamon, buchu, peppermint and the like. Suitable flavour chemicals are in general esters, aldehydes, fatty acids, lactones, and terpene alcohols. Vanillin (4-hydroxy-3-methoxybenzaldehyde) is one example but other suitable flavourings would be well known to the person skilled in the art.
Where two or more liquids are delivered to the beverage the two liquids could, for example, both be colourings, in which case a spectacular visual effect would be created. This would be particularly so if they are injected into the beverage in different positions. Alternatively, both such liquids could be the flavourings, in which case gradients of flavourings could be created, particularly if a thixotropic or thickening agent is also injected into the beverage either together with one or more of the flavourings or separately. Alternatively, each liquid could be a different class of liquid, for example a flavouring and a colouring could be injected at the same time, or at different times, as desired.
It is also possible that a coloured twist as described above, is also flavoured, in which case the flavour will not permeate the entire drink immediately. Thus, gradients of flavour may be created. A typical twist is a twist of juice or juice concentrate.
Colour changes may also be induced in other ways. For example, colour formation by certain food dyes such as cochineal and anthocyanins is pH dependent, and will form different colours depending on whether they are in an acid or alkaline environment. This property could be exploited by containing a beverage at, pH, say, below 7 and using a dye in a weak basic solution as the second liquid. When the container is opened the basic dye solution will be injected into the acidic solution in the container, and will lower the pH of the dye to somewhere below 7, initiating a colour change in the dye. A similar effect could be created by using a chelating agent as the second liquid where the presence or absence of metal ions in the dye effects the colour change in that dye.
Flavour enhancing agents could also be incorporated into the second liquid, for example, the second liquid could constitute an aqueous solution of sugar, a formulated flavour or an artificial sweetener, such as phenylalanine. Whilst this is not particularly advantageous with compounds that are stable in aqueous solution, flavouring agents that are unstable in aqueous solution or flavour enhancers that are unstable in aqueous solution can be added to beverages. This enables these agents to be used when they could not previously be used at all, or had to be added in sufficient quantities to allow for breakdown of a substantial proportion of the compound.
The second flowable material may be any other liquid or other kind of flowable material which it would be desirable to introduce into a beverage. For example, it could be a tea concentrate to be introduced into a juice drink, or vice versa. Another example is the mixing of spirits and a soft drink. The second liquid could also be a thixotropic or thickening agent, a pharmaceutical (and this will be advantageous when, for example, a drug is unstable in aqueous solution but can be stored as a concentrate in ethanol or some other liquid and where it is desirable to administer it by mouth as a dilute aqueous solution or where an undesirable taste in a medicine needs to be masked), quinine concentrate for mixing with carbonated water to create tonic water, or like mixtures.
In some cases where two liquids are mixed, some people prefer more of one liquid and less of the other, or even that one liquid be excluded from the mixture.
Accordingly, the present invention also provides a container in which the concentration of the second liquid in the first liquid can be varied. One means of doing this in the embodiments of the invention where there are means for equilibrating the pressure between the first head space and the second head space, is to provide a bleed hole or valve arrangement in the cap of a bottle. This allows some of the gas from either the first head space or the second head space to be bled gradually. Irrespective of which chamber is bled, the slight pressure differential created will quickly equilibrate so there will be no discharge of the second liquid but the pressure within both head spaces is reduced. Accordingly when the first chamber is opened to the atmosphere there will be created a lesser pressure differential between the second head space and the first head space than would have been created if no gas had been bled. Accordingly, there is a lesser driving force for the second liquid to be expelled from the second chamber. If the pressure in the container has been reduced sufficiently, not all of the second liquid will be expelled from the second chamber so the concentration of the second liquid in first liquid will be less.
Alternatively, if the orifice used to equilibrate pressure between the first head space and the second head space is relatively large, the second liquid will not fully discharge. In this case there will be a tendency to rapid equalisation of pressure when the first chamber is opened to the atmosphere and this will occur to some extent before the orifice is blocked, thus reducing the pressure in the second head space.
Where the second chamber is mounted on the underside of the cap of a bottle it will be appreciated that no opportunity for any further discharge of the second liquid is available if the cap is removed or disposed of. However, if the container is sealed by replacing the cap or if the second chamber is secured within the container, placing a finger over the bottle top and shaking, the second chamber will be pressurized to some extent. When the container is reopened to the atmosphere the second liquid will discharge once again thus, if an extra strong mixture is required instructions could be included on the container to proceed in the manner described above.
Furthermore, one component of a mixture, for example an iced tea concentrate, could be excluded from a juice drink by an arrangement in which, for example, removal of a tab from the bottle cap prior to opening the bottle removes a mechanical blockage from the capillary.
The second liquid may include foaming promoters if it would be advantageous to cause foaming the first chamber when the second liquid is injected therein. Alternatively, the second liquid may contain foaming inhibitors if it is likely that excessive foaming would occur when the second liquid is injected into the first liquid. Suitable foaming inhibitors are lipids, fatty acids, for example oleic acid, and fatty alcohols, for example octanol, and suitable foaming promoters are finely divided salts and powders, proteinaceous materials such as may be derived from barley, and extracts from soapwoods and hops.
Advantageously, the first chamber and/or the second chamber could include active surfaces which promote nucleation. Typically these active surfaces are surfaces on polyolefin structures inserted in the chamber but the entire interior of the chamber could be coated with a polyolefin. In the case of the first chamber, the provision of active surfaces enhances foaming in a beverage contained therein. In the case of the second chamber, the active surfaces maximise decarbonation of the second liquid which provides an additional driving force for discharge of the second liquid.
Tamper proof caps may also overcome the problem of excessive foaming in those beverages prone to this, by allowing the pressure to be released by partially opening the bottle, followed by a separate action to remove the cap fully.
Having provided an arrangement for effectively containing a first flowable material and a second flowable material separately in a pressurised container, and for transferring the second flowable material into the first when the pressurised container is opened, it was found that such an arrangement could also be used to inject gas or a separately contained aliquot of the first flowable material into the major portion of the first flowable material.
Accordingly, in a fourth aspect of the present invention there is provided a container for separately containing a major portion of a first flowable material and a minor portion of a second flowable material (in the form of a liquid or a gas), comprising a first chamber containing the major portion of the first flowable material and having a first head space comprising gas at a pressure greater than atmospheric pressure; a second chamber containing the minor portion of the second flowable material (in the form of a liquid or gas), the gas pressure in the second chamber being at greater than atmospheric pressure; means for transferring gas between the first chamber and the second chamber; means for opening the first chamber to the atmosphere; and means for injecting the minor portion of the second flowable material into the major portion of the first flowable material, when the first chamber is opened to the atmosphere.
The other features of the invention described above with reference to the introduction of a second flowable material (typically a liquid) into a first flowable material (typically also a liquid) are equally applicable to this embodiment of the invention, the exception being that where a gas is injected into the first flowable material (where that material is a liquid), the conduit means for introducing the gas must extend to below the surface of the first flowable material. Preferably, such conduit means extend almost to the bottom of the container (which is typically a bottle). Other adaptations are described with reference to FIGS. 15a-c, 16a-c and 17a-c. 
Moreover, some of the arrangements described above are suitable for delivering a second liquid into a first liquid, a minor portion of the first liquid into major portion of the first liquid, or a gas into the first liquid in arrangements which do not have means for equilibrating the pressure between the first chamber and the second chamber. That is to say, a prepressurised second chamber can be inserted in a bottle or other form of container suitable for use in the invention, and can deliver its contents via the arrangements described above, and such arrangements also constitute a part of the present invention.